NASA's Messenger probe* has sent back some nifty new photos from its first flyby of Mercury, showing unusual craters, evidence of volcanic activity, and oh yes a GIANT SPACE SPIDER!
Actually the spider is an odd rayed crater -- or so they claim -- and we'll undoubtedly get a better look on the next couple of flybys as Messenger chases after the irritatingly fast-moving planet. The probe will encounter Mercury again in October, once more in September of 2009, and finally enter orbit around the planet in March of 2011. Since Mercury is the closest planet to the Sun, it also has the highest orbital velocity. NASA couldn't afford the gigantic booster needed to make up the speed difference between Earth and Mercury in one go, so they've had to make use of gravitational assistance from Venus and Mercury itself. And Mercury's so deep in the Sun's gravity well that any sort of round-trip mission would be completely out of the question. Once you're there, you're there. Which is good, since otherwise we'd be overrun by giant spiders.
*The name is definitely a candidate for Most Tortured Acronym of the New Millennium (MTANM). It ostensibly stands for MErcury Surface, Space ENvironment, GEochemistry and Ranging, which is not only nonsensical but prolix. Why not call it HERALD (Human-Engineered Rocket-powered Automated Learning Device)? Or go whole hog and call it the MERCURY probe (MERCURY)?